The invention relates to an erdosteine dispersing tablet for treating diseases of respiratory systems and a method for preparing the dispersing tablets. The erdosteine dispersing tablet comprises erdosteine, hydroxy propyl celluloses, sodium carboxymethyl starch, polyethylene glycol 4000-6000, microcrystalline celluloses 102, crospovidone, magnesium stearate and povidone K30. The erdosteine is erdosteine monohydrate, a molecular formula of the erdosteine is C8H11NO4S2.H2O, and characteristic diffraction peaks are displayed at 3.323, 8.484, 12.661, 21.823, 30.645, 31.161, 33.209, 36.161 and 38.935 positions of X-ray powder diffraction spectra expressed at diffraction angles of 2 theta+/-0.2 degrees. As discovered in tests, the erdosteine dispersing tablet and the method have the advantages that the erdosteine dispersing tablet is good in stability and high in bioavailability, and problems of poor solubility and compressibility, sticking easiness in production procedures and the like of erdosteine dispersing tablets in the prior art can be solved.